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Dr. Firouz Mojarrad, Mrs. Samira Koshki, Dr. Jafar Masompour, Dr. Morteza Miri,
Volume 4, Issue 4 (1-2018)

Thunderstorm is a destructive atmospheric phenomenon, which annually causes a lot of damage to various parts of human activities. Due to the accompaniment of thunderstorm with rainstorm and hail and its effective role in creating sudden floods, the analysis of the behavior of this hazard has been widely studied both in terms of agriculture and in terms of financial and life damages throughout the world. The study of thunderstorm as a hazardous atmospheric phenomenon using instability indexes in Iran has been less considered due to lack of observation stations. Convective Available Potential Energy (CAPE) and Vertical Wind Shear (VWS) are two indexes that are often used to describe and detect thunderstorm environments. This study evaluates the thunderstorms in Iran with reanalysis data using CAPE and VWS indexes.
Thunderstorm data in 7 different conditions at 8 times a day for 42 synoptic and upper air stations during a 37-year common period (1980-2016) was received from the Iranian Meteorological Organization. At first, frequency, trend and time of occurrence of thunderstorms in Iran were investigated during the statistical period. Then, the ERA-Interim reanalysis dataset of the European Centre for Medium-Range Weather Forecasts (ECMWF) with spatial resolution of 0.5 ° was used for the analysis of thunderstorms. To evaluate the ERA-Interim dataset, the CAPE and VWS values for the 80 selected thunderstorm events that were calculated using the RAOB software were compared with ERA data and their accuracy was confirmed. After confirming the accuracy of ERA data, the average values of CAPE and VWS indexes in 42 stations of the country were calculated based on 4,542 thunderstorm events at 00 and 12 GMT during the study period, and the maps of these two indexes were drawn up using the IDW method. Then, using an equation, the thunderstorm severity thresholds across the country were determined using ERA data with 4,542 thunderstorm events to distinguish between mild, severe and very severe storms. To ensure the selection of important storms, storms with CAPE values of less than 50 were removed to exclude poor environments for convection occurrence. As a result, out of 4,542 thunderstorms, 535 events were eliminated and 4007 events remained. On this basis, a "2 x 2 contingency table" was prepared that compares thunderstorm events and forecasts. This table provides the information required to compute warning performance statistics including POD (Probability of Detection), FAR (False Alarm Ratio) and CSI (Critical Success Index). But the results of these statistics did not match well with the conditions of thunderstorm events in Iran. Therefore, the discriminant analysis was used to differentiate the intensity of thunderstorms and to discriminate mild, severe and extremely severe thunderstorms.
The results of the study showed that thunderstorms in Iran are increasing during the statistical period with a regression slope of 0.23 events per year (8.5 events in the statistical period). The highest frequency of thunderstorms was observed in the month of May with an annual number of 111, and the lowest was observed in January with 12 events. Most thunderstorms occur around 21:30. The highest average frequency of annual events at stations was related to the stations of Urmia, Tabriz, Khorramabad and Bushehr respectively. The proper capability of ERA data to estimate instability indexes in Iran was proved. ERA data provides a very near estimate for VWS, but estimates for the CAPE index are slightly more than observational values. The highest values of the CAPE index are observed in southern provinces, as well as in the southwest of the Caspian Sea coasts, and the highest values of the VWS index are found on the Persian Gulf coasts. When the storm severity breakdown equation for the 400 selected storm events was obtained and the "2 x 2 contingency table" was prepared, it was found that this equation was not satisfactory with respect to the POD, FAR, and CSI indexes. Hence, using the discriminant analysis, the storm severity breakdown relationships and their discriminant equations were obtained. These equations categorized 60% of the surveyed thunderstorms correctly. There is no significant difference between the mean values of CAPE and VWS in the three storm intensity groups. The role of the VWS index was higher in determining the type of storm.

Hamzeh Ahmadi, Gholamabass Fallah Ghalhari, Mohammad Baaghideh, Mohammaf Esmail Amiri,
Volume 5, Issue 2 (9-2018)

Climate change stand as the most important challenge in the future. Horticulture is one of the most sensitive and vulnerable sectors to the climate change. Climate change and global warming will endanger the production of agricultural products and food security. Because of required longer time to fruit production, fruit trees are heavily susceptible to damage from climate change. The purpose of this study was to investigate the impacts of climate change on thermal accumulation pattern in Apple tree cultivation regions of Iran based on the outputs of new CMIP5 models and radiative forcing (RCP) scenarios.
The present study was carried out using a statistical-analytical method. In this study, two types of data was used; baseline data for past period and model output simulation data for the future period. Observation data for baseline period for 53 weather station was extracted from the Iran meteorological organization (IMO). Afterwards, the data for the upcoming period up to the 2090 horizon were processed using the HadGEM2-ES model from the series of CMIP5 models of the MarksimGCM database based on the radiative forcing scenarios RCP8.5 and RCP4.5. The future period will be refined in the mid-term (2020-2055) and the far future (2056-2090). Afterwards, based on the thermal thresholds, thermal accumulation in Apple tree cultivation areas in Iran processed.
The results showed that based on statistical indices on the output of CMIP5 models, the output of the HadGEM2.ES general circulation model is accompanied by fewer simulation errors in illustrating the climate change of the future period than the observation or baseline period. In fact, based on the evaluation criteria or error measures, this model shows a higher compliance with observational data. In general, the model has a lower accuracy than precipitation in the simulation of rainfall, which is due to the complexity of the precipitation process as well as the structure of the climatic models. One of the fundamental issues that have emerged in recent decades is the change in the potential status or heat accumulation of different regions due to the increase in air temperature. The results showed that due to temperature increase, in the mid and far future heat accumulation will increase compared to the baseline period in Apple tree cultivation areas. Increasing of heat accumulation will reduce the length of the Apple tree growth period, and in fact the Apple tree will complete its vegetative and reproductive cycles sooner. This condition will have negative effects on the quality, taste and color of the Apple varieties. For example, according to the RCP8.5 scenario in the physiological threshold of the apple tree 4.5 C° , in the mid term (2020-2055) and far future (2056-2090) will be 1132 and 2171 active degree days respectively compared baseline period. These conditions equivalent to the  51% and 42% respectively. Based on the RCP4.5 scenario, these conditions will be 390 and 680 active degree day, equivalent to 9.3% and 15.1%, respectively, compared to the baseline period.
The results showed that the heat accumulation in Apple tree cultivation areas in the future period will increase compared to the baseline period. One of the most important effects of climate change on the Apple tree  cultivation will be due to increased heat accumulation in the upcoming period. Increasing the heat accumulation will reduce the length of fruit tree growth period, and in fact the fruit tree will complete its vegetative and reproductive cycles earlier. According to these conditions, the areas of Apple tree cultivation in the future will be extended to higher regions. These conditions are important for cold regios fruit tree such as Apple tree, in facr increase in heat accumulation will reduce the length of the growing season and, as a result, reduce the quality and yield of the fruit. Based on the spatial distribution, the least heat accumulation in the highlands, especially Northwest and central Alborz, will occured. In natural landscapes of low elevations, valleys and plains in the Northeast, central Southern part of the Zagros and around Lake Urmia, higher heat accumulation will occured in the future. Therefore, one of the effects of climate change on fruit trees will be due to increased heat accumulation in the upcoming period. Increasing the potential or heat accumulation will reduce the growth period of the fruit trees, in fact, the fruit trees will complete their vegetative and reproductive cycles sooner.
Kamal Omidvar, Mehdi Mahmodabadi, Parisa Shams, Mahbobeh Amiri Esfandegheh,
Volume 7, Issue 3 (11-2020)

Due to the fact that the mechanism of anticyclone Movements is the desire to descend and suppress the air, so the effect of these movements and their location in the occurrence of flood falls is significant. For this purpose, in this paper, flood precipitation in the last two decades of Kerman province was studied and two of the most severe ones were selected. Due to the emphasis of this paper on the province of Kerman, the heavy rainfall was calculated for each station in the province using the Gumble Type 1 Distribution Statistical Index. Then, the thermodynamic properties of the precipitation were analyzed using radial data and Kerman station's sketch diagram. For analysis of these floods, daily rainfall data of the synoptic station 10 of the province and sea surface pressure maps and850,500,300 hectopascal levels were used. Then, the arrangement of the simulated pattern and its trend in the air maps, were studied during a selective period daily3. The results of the study indicate that the main cause of flood precipitation in the study area is to strengthen the eastern Mediterranean landfall in the middle troposphere, so when moved downward to the bottom of the polar system, it is transmitted to lower latitudes As a result, Western systems, with their movements on the southern warm waters, have a high moisture content and cause heavy rainfall in the region. Also noteworthy in the occurrence of precipitation is the presence of intense swinging movements on the southern waters, especially the Oman Sea, which causes more humidity to be injected into the interior areas of the country and provides the conditions necessary for the occurrence of such rainfall.

Hossein Varjavand Naseri, Asghar Tahmasbi, Hasan Darabi, Ahmadreza Yavari, Mohammadjavad Amiri, Gholamreza Nabi Bid Hendi,
Volume 7, Issue 4 (2-2021)

   Extended Abstract:
The increasing challenge of water in many regions of the country is rooted in inappropriate governance of water resources at the basin levels. Investigating the interactions of different stakeholders and institutional arrangement affecting it is one of the key elements of governance system. The most important obstacle to achieving the optimal governance model of water resources in developing countries is the unknown path from governmental management, to good governance. The analysis of stakeholders and influential entities on their interactions is considered as one of the important pillars of governance assessment frameworks.
Accordingly, the purpose of this study is to evaluate the water resources of Zayandeh roud basin from the perspective of interactions between actors and formal institutions affecting their interactions. In this regard, it is attempted to answer two main questions: firstly, what is the organizational structure in management of Zayandeh roud?, Second, how far are the organizations’ policies and programs involved in the management of the watershed ?
In this study, Isfahan, Chaharmahal - bakhtiari , Khuzestan and Yazd which are related to the river basin issues, were selected for social network analysis. Organizations and governmental and non- governmental institutions related to the process of sustainable management were questioned. In this regard, according to the numerous studies conducted in the field of Zayandeh roud and Gavkhoni wetland , the number of organizations and related institutions were identified. Then, the network matrix of actors’ policy and collaboration was formed and centrality indices of input and output grades and betweenness centrality indices were measured through Ucinet software.
There are a wide range of active actors in management of Zayandeh roud river basin, each in an attempt to obtain more water resources from this river. As mentioned in the conceptual framework of the research, two key aspects are investigated. Key stakeholders analysis and their role in water resource management and review of actors ' policies in water resource management in two dimensions of belief in changing policies, and the need to change policy from the viewpoint of other actors. Accordingly, the research findings are presented in the following parts.
  • decision making and facilitating information flow
  • Power and control of actors in the network of organizational collaboration
  • Co - ordination role in the enterprise - cooperative network
The findings of this research show that in the dimension of capacity and flow of information watershed management, Regional water organization in Isfahan province and in the next rank of water resources management, Zayandeh roud coordination council and Isfahan provincial governor are organizations that have high output degree and can play a key role in information flow. In other words, information that is necessary for the actors and other organizations is better flowed by these organizations.
In terms of supervision on the network of interactions and control over other actors in the basin, which was measured with the degree of centrality of input, Isfahan parliament representatives in the first and the agriculture jihad of Isfahan province gained the highest rank respectively. After these organizations which are mainly government and dependent entities, non - governmental organizations of three other provinces have the lowest rank in terms of ability to control the network. The lower power of NGOs in the social network of the organization indicates a low planning system for the management of the watershed. Comparative studies in the river basin show that the feature of the extent and diversity in the social - ecological system of a watershed among several distinct political areas can reveal the importance of the position of organizations that have a bargaining power in the watershed management network.
Betweenness centrality index in information exchange network has a fundamental role. The actors with the intermediary rate and high control power among the organizational stakeholders are the same organizational entrepreneurs who have an important role in establishing relationships and increasing interactions among other actors. If the actors with high degree of mediation are removed from the network, information exchange in the network will be disrupted.
It is obvious that without knowing these corporate entrepreneurs or in other words, actors with high mediation ability in the exchange information network, any activity in the direction of comprehensive management of land and sustainable development will be associated with time and cost. In connection with the task of coordination in watershed management, the Jihad of agriculture organization, department of environment and water room committee of Isfahan have obtained the highest degree of betweenness centrality which seems to be a suitable place due to their organizational functions. In this regard, attention and reinforcement of organizations such as NGOs and parliament representatives of three other provinces and provincial governor of these three provinces with low degree of betweenness centrality can be suggested. The lack of such interaction is undoubtedly one of the challenges facing sustainable management of the region. According to the results of other studies, it can be said that to achieve sustainable and integrated management of land and preservation of natural areas, it is necessary to study the pattern of relationship between organizational stakeholders.
The results show that the Regional water organization of Isfahan province and the Zayandeh roud coordination council have a higher position in decision making and information flow. On the other hand, the high performers of water resources such as Iran’s water resources management company and the Zayandeh roud coordinating council and in the next level, Regional water organization, the provincial governor and the parliament representatives of Isfahan are the best critics of the watershed governance. In contrast policies of jihad agricultural organization, farmers and Regional water organization of Isfahan have been criticized by other actors.

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